Yesterday’s announcements about the potential of graphene as an energy storage material for super-capacitors are definitely exciting. As I mentioned last week in my August top story roundup, energy storage is one of the biggest nuts we need to crack to get renewable energies over the tipping point. “Ultracapacitors” are an enticing alternative to batteries for this purpose, and graphene appears to offer a significant improvement in capacitative storage:
“There are reasons to think that the ability to store electrical charge can be about double that of current commercially used materials. We are working to see if that prediction will be borne out in the laboratory,” said Rod Ruoff, a mechanical engineering professor and a physical chemist at the University of Texas at Austin.
Graphene is a special form of carbon in which the carbon atoms are linked into a sheet one atom thick. It’s highly conductive in the plane of the sheet. Because the sheet is only a few nanometers thick, the story has been presented as a “nanotech” breakthrough. However, as discussed in the April Technology Review report on a new, much cheaper and faster way to make graphene sheets, current means of producing graphene don’t use nanotechnology – just a highly miniaturized industrial process.
As Technology Review reported, a team from Rutgers is making graphene sheets starting with a graphene “slurry” suspended in water. The slurry is laid down on a nanoscale filter and the water drained off, leaving a film of graphene one to five nanometers thick and a few centimeters wide. This is essentially the way paper is made (an industrial process) even though the filter used has nanometer scale holes.
A key basis of Ray Kurzweil’s assertion that alternative energy will obey a Moore’s Law-like exponential price-performance curve is that it’s an “information technology.” By this he means that it can be done using a digital approach. A nanotech assembly or manufacturing process that worked by placing individual atoms in place according to a “program” would be the apotheosis of such an approach.
So my prediction – and there is some research in this area, some of it related to nanotubes – is that graphene is an ideal first product for a truly nanotech manufacturing approach. The material itself is very simple, consisting simply of carbon atoms. It’s a fairly low-energy arrangement – graphene is a component of graphite (which is partly made up of small sheets of graphene), which is itself very common. You can imagine, in your mind’s eye, a nano assembly robot (like the ones you sometimes see in car commercials, but infinitely smaller) grabbing a carbon atom, swinging it around onto a partially-assembled graphene sheet, and slotting it in with a satisfying “clunk.”
Even if the initial foray into nano-assembly of graphene is expensive and difficult, due to the nature of information technology, it will gradually, then with increasing speed, get cheaper.
I’d love to hear your comments about this prediction, and about graphene’s potential in general.